Photon counting detectors such as single-photon avalanche diode (SPAD) arrays can be utilized to improve the sensitivity of optical wireless communication (OWC) systems. However, the achievable data rate of SPAD-based OWC systems is strongly limited by the nonlinearity induced by SPAD dead time. In this work, the performances of SPAD receivers for two different modulation schemes, namely, on-off keying (OOK) and orthogonal frequency division multiplexing (OFDM), are compared demonstrating contrasting optimal regimes of operation. We employ nonlinear equalization and peak-to-average power ratio optimization by adjusting the OFDM clipping level to achieve record experimental data rates of up to 5 Gbps. In particular, the experimental results demonstrate the achievable data rates of 3.22 Gbps and 5 Gbps when OOK and OFDM are employed, respectively. It is also illustrated that to achieve the best data rate performance over a wide range of received power, adaptive switching between OOK and OFDM may be utilized.
翻译:光子计数探测器,如单光子雪崩二极管(SPAD)阵列,可以用来提高光学无线通信系统的灵敏度;然而,SPAD的OSWC系统的可实现数据率由于SPAD死时引起的非线性差而受到严重限制;在这项工作中,SPAD接收器在两种不同的调制方案,即离线键(OOK)和正方位频率分解多路(OFDM)的性能比较显示最佳运作机制;我们采用非线性均匀和峰值对平均电动比率优化办法,调整ODM剪切率,以达到高达5Gbps的记录实验数据率;特别是,实验结果显示,在使用OOK和ODM时,可实现3.22Gbps和5Gbps的数据率;还说明,为了在广泛获得的动力中实现最佳数据率性差,可以使用OOK和ODM的调换。